Chlamydia trachomatis pulmonary infection induces greater inflammatory pathology in immunoglobulin A deficient mice

Cell Immunol. 2004 Jul;230(1):56-64. doi: 10.1016/j.cellimm.2004.09.002.


Chlamydia trachomatis is an intracellular bacterial pathogen that primarily infects via mucosal surfaces. Using mice with a targeted disruption in IgA gene expression (IgA(-/-) mice), we have studied the contribution of IgA, the principal mucosal antibody isotype, in primary immune defenses against pulmonary C. trachomatis infection. Bacterial burden was comparable between IgA(-/-) and IgA(+/+) animals following C. trachomatis challenge. Serum and pulmonary anti-Chlamydia antibody levels were higher in IgA(-/-) animals, with the exception of IgA. Lung sections of challenged IgA(-/-) mice showed more extensive immunopathology than corresponding IgA(+/+) animals. Real-time PCR analysis demonstrated significantly greater IFN-gamma and TGF-beta mRNA expression in IgA(-/-) as compared to IgA(+/+) animals. Together, these results suggest that IgA may not be necessary for clearance of primary C. trachomatis infection. However, IgA(-/-) mice displayed exaggerated lung histopathology and altered cytokine production, indicating an important role for IgA in regulating C. trachomatis induced pulmonary inflammation and maintenance of mucosal homeostasis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Bacterial / blood
  • Antibodies, Bacterial / immunology
  • Chlamydia Infections / immunology*
  • Chlamydia Infections / metabolism
  • Chlamydia Infections / microbiology
  • Chlamydia Infections / pathology*
  • Chlamydia trachomatis / physiology*
  • Gene Deletion
  • HeLa Cells
  • Humans
  • Immunoglobulin A / genetics
  • Immunoglobulin A / immunology*
  • Interferon-gamma / genetics
  • Lung / immunology
  • Lung / microbiology*
  • Lung / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Transforming Growth Factor beta / genetics


  • Antibodies, Bacterial
  • Immunoglobulin A
  • RNA, Messenger
  • Transforming Growth Factor beta
  • Interferon-gamma